CORVUS SYSTEMS THE BANK SERVICE MANUAL

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CORVUS SYSTEMS, Inc. warrants all its hardware and software for a period of 180 days from the date of purchase from any authorized Corvus Systems dealer. Should the product fail to be in good working order at any time during this period, Corvus Systems will, at its option, repair or replace this product at no additional charge except as set forth below. Repairs will be performed and non-functioning parts replaced either with new or reconditioned parts to make the product function according to the company standards and specifications. All replaced parts become the property of Corvus Systems, Inc. This limited warranty does not include service to repair damage to the product resulting from accident, disaster, misuse, abuse or modifications that are unapproved by Corvus Systems.

limited Warranty service may be obtained by delivering the product during the 180 day warranty period to Corvus Systems with proof of purchase date. YOU MUST CONTACT CORVUS CUS- TOMER SERVICE TO OBTAIN A "RETURN MERCHANDISE AUTHORIZATION" PRIOR TO REfURNING THE PRODUCT. THE RMA (RETURN MERCHANDISE AUTHORIZATION) NUM- BER ISSUED BY CORVUS CUSTOMER SERVICE MUST APPEAR ON THE EXTERIOR OF THE SHIPPING CONTAINER ONLY ORIGINAL OR EQUIVALENT SHIPPING MATERIALS MUST BE USED. H this product is delivered by mail, you agree to insure the product or assume the risk of loss or damage in transit, to prepay shipping charges to the warranty service location and to use the original shipping container. Contact Corvus Systems or write to the Corvus Systems Service Center, 2029 O'Toole Ave., San Jose, CA 95131 prior to shipping equipment.

ALL EXPRESSED AND IMPliED WARRANTIES FOR THIS PRODUCT, INCLUDING THE WAR- RANTIES OF J\lliRGIANTABIUTY AND FITNESS FOR A PARTICUlAR PURPOSE, ARE LIMITED IN DURATION TO A PERIOD OF 180 DAYS FROM DATE OF PURCHASE, AND NO WARRAN- TIES, WHETI-IER EXPRESSED OR IMPLIED, WILL APPLY AFTER THIS PERIOD. SOME STATES DO NOT ALLOW UMITATIONS ON HOW LONG AN IMPLIED WARRANTY LASTS, SO THE ABOVE liMITATIONS MAY NOT APPLY TO YOU.

IF THIS PRODUCT IS NOT IN GOOD WORKING ORDERAS WARRANTED ABOVE, YOUR SOLE REMEDY SHALL BE REPAIR OR REPLACEMENT AS PROVIDED ABOVE. IN NO EVENT WILL CORVUS SYSTEMS BE liABLE TO YOU FOR ANY DAMAGES, INCLUDING ANY LOST PROFITS, LOST SAVINGS OR OTHER INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF OR INABIliTY TO USE SUCH PRODUCT, EVEN IF CORVUS SYSTEMS OR AN AUTHORIZED CORVUS SYSTEtvlS DEALER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY.

SOME STATES DO NOT ALLOW THE EXCLUSION OR liMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR CONSUMER PRODUCTS, SO THE ABOVE UMITATIONS OR EXCLUSIONS MAY NOT APPLY TO YOU.

THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH MAY VARY FROM STATE TO STATE.

FCC WARNING

This equipment complies with the requirements in Part 15 of FCC Rules for a Class A comput- ing device. Operation of this equipment in a residential area may cause unacceptable interference to radio and TV reception requiring the operator to take whatever steps are necessary to correct the interference.

NOTICE

Corvus Systems, Inc. reserves the right to make changes in the product described in this manual at any time without notice. Revised manuals will be published as needed and may be purchased from authorized Corvus Dealers.

This manual is copyrighted and contains proprietary information. All rights are reserved. This document may not, in whole or in part, be copied, photocopied, reproduced, translated, or reduced to any electronic medium or machine readable form without prior consent, in writing, frOIn Corvus Systems, Inc.

CORVUS SYSTEMS, Inc.

2029 O'Toole Avenue San Jose, CA 95131 Telephone: (408) 946-7700 TELEX: 278976

The Corvus Concept,'" Transporter,'" Corvus OMNINET, '" Corvus LogiCalc,'" Time Travel Editing,'"

EdWord,'" Constellation,'" Corvus,'" Corvus Systems,'" Personal Workstation,'" Tap Box,'" Passive

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PART NO.: 7100-05219

RELEASE DATE: 15 MARCH 1984

CORVUS SYSTEMS THE BANK SERVICE MANUAL

This document contain three types of notations. These are, in increasing order of importance,

NOTE, CAUTION, and WARNING. The NOTE indicates some action to be taken to speed or

simplify a procedure. The CAUTION indicates that pontential damage to the equipment or user data exists, and care should be taken to avoid this. The WARNING indicates that potential hann or injury to the service technician or operator exists, and extreme care should be taken to avoid these.

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LIST OF FIGURES AND TABLES

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Figure I-I.

1-2.

1-3.

1-4.

1-5.

2-I.

2-2.

2-3.

2-4.

2-5.

2-6.

2-7.

2-8.

2-9.

2-10.

2-11.

2-12.

2-13.

2-14.

3-I.

3-2.

3-3.

5-I.

5-2.

5-3.

5-4.

5-5.

5-6.

5-7.

5-8.

5-9.

6-I.

6-2.

6-3.

6-4.

Table I-I.

1-2.

2-1.

2-2.

6-I.

6-2.

6-3.

LIST OF FIGURES AND TABLES

Page

Bank Installation Package ... , 1

Major Assemblies. . . .. 2

Bank Front View ... , ... 3

Bank Rear View . . . .. 4

Tape Break-Out Tab ... , ... , ... 6

Bank Block Diagram ... , .... , ... , .... , ... , 9

Tape Drive Mechanism ... 10

WDI0I0 Architecture ... 12

R/W Board Block Diagram ... , ... 13

Auto Clear Circuit ... 14

Stepper Motor Circuit ... 15

Index Detection Circuit ... 16

Track Zero Detection Circuit ... 17

Servo Board Block Diagram ... 18

Servo Control IC ... 19

Constant Voltage Circuit ... 19

Differential Voltage Amplifier Circuit ... 20

Motor Driver Circuit ... 20

FG-Amp and Waveform Shaping Circuit ... 21

Tape Cartridge Holder ... 25

Read/Write CPU Board ... 27

Power Supply Connectors ... 29

Read/Write Head Cleaning ... 40

Tracking Area Guides ... 41

Capstan ... 41

Cartridge Support Assembly Lubrication ... 43

Worm Tracking Gear Lubrication ... 44

Leaf Switch Locations ... 45

Cartridge Detect Switch Adjustment ... 45

Placement Detect and Write Protect Switch Adjustment. ... 46

Servo Motor Speed Adjustment ... 47

Fuse Replacment ... 53

Power Connector and Switch Assembly ... 54

Power Harness ... 55

OMNINET Bank Controller ... 57

Page Cartridge Tape Specifications. . . .. 5

Tape Specification Table. . . .. 5

Coil Activating Sequence ... 16

CPU Error Signal Status ... 18

Indicator Operating Conditions ... 51

Indicator Error Conditions ... 52

AC Power Connector ... 55

xi

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SPECIFICATIONS

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SPECIFICATIONS

Cabinet Width Height Weight Top Loading Tape Drive Tape Speed Recording Format Data Transfer Data Density Number of Tracks Available to User Reserved Firmware landing

Track Density Track pitch Seektime:

1 track Latency

100-MB Tape 200-MB Tape Settling time Interface MTBF MTTR

Data Integrity . Soft errors Hard errors Format

Depth 16.0 inches / 40.64 cm 12.0 inches / 30.5 cm 5.75 inches /14.6 cm 19 lbs / 8.5 kg (no cartridge)

18 feet /5.5 meters per second Modified Frequency Modulation 1 million bits per second

4620 bits per inch 101

99 1 1

254 tracks per inch 100 micrometers

20 milliseconds per track 12 seconds

21 seconds 300 milliseconds Corvus OMNINETTM 1500 hours

30 minutes 1 in 1 X lOs bits 1 in 1 X 10¹¹11 bits Soft sector 4 or 8 logical tracks per physical track 256 Sectors per logical track

4 Spare sectors per physical track Power

100/110 or 220/240 VAC, 50-60 Hz

41°F to 90°F / SoC to 32°C 30% to 80%

Environmental Operating

Temperature Relative Humidity

Altitude

o

to 10000 feet /0 to 3050 meters Storage

Temperature Relative humidity

32°F to 122°F / O°C to 50°C 10% to 85%

xv

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Tape Cartridge Tape Width Tape length:

100-MB 200-MB Tape loop time:

100-MB 200-MB

Memory capacity:

100-MB unformatted formatted 200-MB

unformatted formatted Depth Width Height Weight

100-MB 200-MB Tape life

liz

inch 1 12.7 mm 173.7 feet 1 53 meters 337.8 feet 1103 meters

9.7 seconds 18.8 seconds

1.14 MB per track 1.03 MB per track 2.28 MB per track 2.07 MB per track 5.5 inches 1 140 mm 5.5 inches 1 140 mm 1.5 inches 1 36 mm

9.34 ounces 1 265 grams 10.05 ounces 1285 grams 500 hours spinning 500 startsl stops

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CHAPTER 1 GENERAL DESCRIPTION

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1.0 Scope of Chapter

CHAPTER 1 GENERAL DESCRIPTION

This chapter provides an overall view of the Bank. Its use, major assemblies, and external features are described.

Receiving instructions and a summary of installation procedures are given. The chapter concludes with a description of the Bank tape cartridges and their care and storage.

1.1 Introduction

The Bank Service Manual is designed for service technicians who perform maintenance or warranty service on the Corvus Bank. For ease of maintenance the Bank has been designed as a group of replaceable modules. Corvus recommends that service be limited to module replacement and to maintenance procedures described in this manual.

1.2 General Description

The Bank is a continuous loop tape· drive primarily designed as an archivial backup device for the Corvus OMNINET Local Area Network. The recording tape is safely housed in a removable cartridge. A single read/write head can be positioned vertically at 101 locations, called tracks, on the tape.

1.3 Receiving the Bank

The Bank installation package should contain five items: the Bank, an AC power cord, one OMNINET tap cable, one OMNINET tap box, and a manual. Tape cartridges are purchased separately.

The Bank Power Cord Tap Cable Corvus Tap Box'"

Figure 1-1. Bank Installation Package

The Bank should be carefully unpacked and checked for shipping damage. External evidence of rough handling may be symptomatic of damage to the delicate mechanisms within the device.

NOTE:

Any damage claims must be reported to the local office of the shipper so an inspection may be made, and a damage report filed. If the damaged equipment is a new product, the Corvus Order Processing Department must be con- tacted for proper return procedures. If the damaged equipment is a recently serviced product being returned under an RMA (Return Merchandise Authorization) number, contact the Corvus Customer Service Department for proper return procedures.

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The Bank is manufactured in two models; one for use with 100-110 VAC, the other for use with 220-240 VAC. The voltage rating is written on the metallic serial number label on the rear of the cabinet. If the voltage rating is not com- patible with the local voltage, contact your Corvus dealer.

1.4 Major Assemblies

The Bank is comprised of five modular units. These are:

• Tape Drive Mechanism

• OMNINET Bank Controller Board

• Read/Write CPU Board

• Servo Board

• Power Supply

Read/Write ___ _{CPU Board}

+-ta*======================>

Tape Drive - - - t r - t - - - - t

Mechanism

OMNINET Bank Controller

l : I l l l - - - t f - - - - -Power Supply Assembly

Servo Board

Figure 1-2. Major Assemblies

Each is replaceable as an individual module for ease of service.

1.4.1 Tape Drive Mechanism

Manufactured for Corvus by Tokyo Electric Corporation, the tape drive mechanism can be divided into functional subassemblies:

• Tape Cartridge Holder and Support Assembly

• Read/Write Head and Tracking Unit

• Stepper Motor

• Capstan and Servo Motor

• Tape Load Solenoid

• Sensor Switches

These subassemblies are described in section 2.2

2

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1.4.2 OMNINET Bank Controller Board

The Transporter, Disk Server, and Tape Controller are the three functional areas of the OMNINET Bank Controller.

This board, the largest of all the Bank's PCA's, is positioned parallel to the cabinet sides nearest the left side when viewed from the front of the Bank. Section 2.3 of this manual provides a functional description of this board.

1.4.3 Read/Write CPU Board

Mounted between the OMNlNET Controller and the tape drive mechanism, the Read/Write functions and mechanical operations controlled by this board are described in section 2.4.

1.4.4 Servo Board

The servo board drives the tape servo motor. This small board is mounted between the power supply board and the tape drive mechanism. The servo board function is discussed in section 2.5.

1.4.5 Power Supply

A single power supply provides all DC voltages used by the Bank. The power supply is the rearmost assembly inside the cabinet, adjacent to the AC power supply plate. Section 2.6 details the power supply and fuse.

1.5 Switches and Indicators

Switches, buttons, and indicators used in normal operation are located on the outside of the cabinet to provide user access.

1.5.1 LED Indicators

There are three indicator Light Emitting Diodes (LED's) on the front panel of the Bank; READY, BUSY, and FAULT.

After the system has come ready as described in section 1.6 the READY light only will be on. Section 6.2 gives details of the possible indicator light combinations and associated conditions.

1.5.2 Tape Eject Button

The tape eject button is on the top of the Bank cabinet just in front of the tape cartridge holder. This is used to open the tape cartridge holder to install a cartridge or to remove a cartridge.

~::~:::::§~a==~~Li1I:'---

Tape Cartridge Holder

~~---Eject

Indicators

Figure 1-3. Bank Front View

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1.5.3 RESET Switch

The power to the Bank should not be turned off while the tape servo motor is running nor should a tape cartridge be removed. Normally the motor will stop within 60 seconds after the last command; the servo motor audibly stops and the tape solenoids (see section 2.2.5) can be heard to disengage.

Should the motor fail to stop, the RESET button may be used to disengage the servo motor. The RESET button is the small round button on the rear panel between the power socket and power switch. Press the RESET button. When the servo motor has stopped and the solenoids have disengaged, the tape may be ejected or the power turned off.

RESET

AC POWER - - - 1 - - + + 1

AC POWER RECEPTACLE

o

OMNINET MOLEX

:~--~---CONNECTOR ::;t:tl-_ _ _ _ +-____ OMNINET ADDRESS

SWITCHES

Figure 1-4. Bank Rear View

1.5.4 Network Address Switches

Each network device must have a unique "address:' For the Bank, this is done by setting the eight microswitches, DIP switches, on the rear of the Bank, immediately below the OMNINET connector. Choose an address from 1 to 63; 0 is reserved for the OMNINET Disk Server. Set switches 1 to 6 to correspond to the selected address. Switches 7 and 8 should both be set OFF or OPEN.

A table of switch settings for each address can be found in The Bank Guide or the OMNINET Installation Guide.

1.6 Installation To install the BANK:

1. Install the OMNINET tap box at the desired location on the trunk line. Leave a minimum of 5 feet (1.5 meters) between tap boxes on the trunk.

2. Set the OMNINET address.

3. Plug the phono-jack end of the tap cable into the tap box; plug the other end into the Molex connector on the rear of the BANK

4

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4. Attach the AC power cord to the Bank and then to the power outlet.

5. Turn on the Bank's power switch on the rear of the cabinet.

6. Place a tape cartridge in the holder and close the holder.

The tape load solenoid will cause the pinch roller to hold the tape against the capstan and place the tape across the head assembly. The head will seek to track 0 and the tape will spin-up to speed. When a tape correctly configured for use is in place, the BUSY LED will go on for approximately 30 seconds, then only the READY LED will remain on.

(Instructions for formatting a tape may be found in the Bank Guide.) If the Bank does not come ready, see the dis- cussion of the LED indicators in section 6.2.

Complete instructions for the installation and use of the Bank can be found in the following manuals:

• The Bank Guide

• Transfer Utility Manager's Guide 1.7 Bank Cartridges

Bank tapes are available in 100 and 200-megabyte (abbreviated MB) capacities. Tape specifications are given in Table 1-1.

Memory Capacity Tape Length Tape Loop Time

200-MB 103 Meters 18.8 ±.4 Sec

100-MB 53 Meters 9.7 ±.3 Sec

Table 1-1. Cartridge Tape Specifications

1.7.1 Tape Tracks

There are 101 tracks on a tape. Track 0, or the landing track, is the track to which the head is moved at power-up.

Firmware is resident on track 1 and the remaining tracks, 2 to 100, are used for data storage.

Each tape is divided into segments or "heads:' Each head is composed of 256 sectors. There are 4 heads on a 100-MB tape and 8 heads on a 200-MB tape.

Four sectors are reserved on all tapes for spares in the event of tape defects; this yields a total of 1020 user sectors on a 100-MB tape and 2044 user sector in 200-MB tape. If a defective sector is found, one of the spare sectors may be used as a substitute.

The table below provides a quick reference of these specifications.

Segments Sectors Sectors

Capacity or Per Per

Heads Head Track

--

100 MB 4 256 1020

--

200MB 8 256 2044

--

Table 1-2. Tape Specification Table

Bytes Per Sector

1024

Spa re ks- ors Trac Sect 4

--~ ---~----

4

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1.7.2 Care and Storage of Tapes

Like any magnetic recording medium, Bank tapes require careful handling and storage.

• Never touch the tape surface.

• Never disassemble a tape cartridge.

• Store each cartridge in its protective sleeve when not in use.

CAUTION:

Moisture may condense on the tape if the cartridge is brought into a warm room from the cold outdoors during the winter. This moisture can cause damage to the tape or the Bank mechanism. Let the cartridge warm up to room temperature before using it.

• To prevent accidental erasure of a tape, remove the ''break-out'' tab on the bottom corner of the cartridge; the tape may not then be used to record. To again use the cartridge for recording, cover the hole with a piece of cellophane tape.

To prevent accidental erasure To record again

Figure 1-5. Tape Break-Out Tab

6

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CHAPTER 2 FUNCTIONAL DESCRIPTION

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CHAPTER 2 FUNCTIONAL DESCRIPTION

This chapter provides a functional description for the Bank hardware. Presented first will be a general block diagram of the major assemblies followed by detailed circuit descriptions. Corvus recommends that troubleshooting be limited to exchange of one of the failing major assemblies or adjustments as outlined in chapter 5.

Included in this chapter are detailed circuit descriptions to assist qualified technicians in functional understanding of the Bank to a discrete component level. This is for informational purposes only; PERFORMING COMPONENT LEVEL REPAIR MAY VOID THE WARRANTY ON THE BANK

2.1 Introduction

As shown in figure 2-1, the Bank is made up of five major assemblies. In servicing the Bank these five assemblies are replaceable modules. The three LEDs on the front panel of the Bank are mounted to a paddle board. The LEDs are not individually replaceable, but the paddleboard can be replaced.

OMNINET L.OCALAREA

NETWORK

~

OMNINET CONTROLLER

BOARD

j~

POWER SUPPLY

2.2 Tape Drive Mechanism

READ/WRITE SERVO

.. ^.,

^BOARD

^.... ^.,

^BOARD

I

,,, ,

,~ \~

-

_DRIVE^TAPE

MECHANISM

Figure 2-1. Bank Block Diagram

The tape mechanism is manufactured by Tokyo Electric Corporation to Corvus specifications. All moving parts of the Bank are contained within this assembly. Its purpose is to: 1) guide the tape cartridge during loading and ejecting, 2) sense for a loaded cartridge, 3) sense for a write protected cartridge, 4) load the tape against the capstan and read/write head, 5) move the tape, 6) move the read/write head to a specified track, and 7) read/write data on the tape.

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Figure 2-2. Tape Drive Mechanism 2.2.1 Cartridge Holder Assembly

The cartridge holder is simply a mechanical device which loads and ejects the tape cartridge. Springs, levers, and the metal frame are designed for special Bank cartridges only. A leaf switch on the holder's right side (when viewed from the front) is a sensor for loading and ejecting cartridges.

2.2.2 Read/Write Head

A single read/write head is mounted on the head positioner assembly. Like most recording heads it is made of a set of induction coils which produce and detect magnetic fields. During write operations a frequency modulated signal is sent through the coils and is recorded on the surface of the tape as it moves past the head. During read operations the same set of coils detect the recorded signal and passes it to the Read/Write CPU board.

2.2.3 Head Tracking Unit and Stepper Motor

The head tracking Unit positions the head over the appropriate track of the tape. The positioner is composed of a stepper motor, gear train, sensor, and worm gear. The read/write head is moved vertically by rotation of the worm gear.

The stepper motor, located under the tape drive, turns the worm gear via one idler gear and simultaneously turns two other gears which are used to sense the track zero position. Counterclockwise rotation of the worm gear moves the head down towards track zero, while clockwise rotation moves the head upward toward track 100.

2.2.4 Servo Motor and Capstan

The capstan is a precision roller which controls movement of the tape. The capstan is driven directly by the drive servo motor located on the underside of the capstan. The tape is held against the capstan by a pinch roller. A felt brake pad stops the capstan after each tape movement operation.

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2.2.5 Pinch Roller or Tape Load Solenoid

The pinch roller solenoid, also called the tape load solenoid, operates after a tape cartridge is inserted. It causes the pinch roller to hold the tape against the capstan, while at the same time it disengages the capstan brake. The solenoid is controlled by circuitry located on the Read/Write CPU board. No field adjustments can be made to the solenoid or associated levers.

2.2.6 Unload Solenoid

Activated when the servo motor stop signal is generated, the unload solenoid controls the tape position as the tape is stopped.

2.2.7 Tape Hold or Tape Curb Solenoid

The tape hold or tape curb solenoid is located at the rear of the mechanism assembly. It ensures that the tape is properly aligned while spinning. It also ensures proper tension and reduces tape slack when stopping. A tamper pad, located inside the tape cartridge, is activated by a lever which projects up into the cartridge when the cartridge is loaded into the drive.

2.2.8 Sensor Switches

There are three switches associated with the tape mechanism. One is located on the cartridge holder assembly while the other two are located at the rear of the mechanism assembly. The cartridge detect switch, located on the side of the cartridge holder is used to disable tape operations while loading or ejecting a cartridge. The other two switches, located at the rear of the mechanism, sense for a properly loaded cartridge and for a write protected cartridge.

2.3 OMNINET Bank Controller Assembly

The OMNINET Bank Controller is an intelligent controller which interfaces the Bank to the Corvus OMNINET. It supports all commands which are implemented on a Corvus Winchester Drive. The Bank OMNINET Controller can be divided into three main functions:

• OMNINET Transporter

• Disk Server

• Tape Controller

This board has 10K x 8 bits of static RAM which is contained in 5 socketed chips. The RAM is shared for the three main functions listed above. 2K is used by the disk server and 2K for the tape controller buffer. The remaining 6K is utilized by the 6801 microprocessor which is part of the OMNINET transporter.

2.3.1 OMNINET Transporter

The transporter section of the controller board utilizes the standard OMNINET chip set:

• 6801 Microprocessor

• Corvus Monochip

• Advanced Data Link Controller

• RS422 Transmitter and Receiver

The MC6801 is the heart of the OMNINET chip set. It is an 8-bit, single-chip microprocessor which contains a 2K X 8 bits internal ROM and internal RAM of 128 bytes. The MC68A54 Advanced Data Link Controller (ADLC) interfaces to the RS-422 transmitter and receiver and the remainder of the transporter. The Corvus Monochip is a custom gate array which provides timing and control for all data transfers and decodes 6801 activity. Two other socketed chips included in the basic chip set are the transmitter and receiver. A low-power 75174 provides the transmitter functions and a low-power 75175 provides the receive functions in RS-422 format. For further information on the OMNINET chip set refer to the Networks Service Manual.

2.3.2 Disk Server

The Disk Server provides the interface to and from the OMNINET transporter and the tape controller. The server section utilizes the same chip set as the transporter; it adds additional circuitry and memory buffers to translate Con- stellation protocol to disk drive commands.

11

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2.3.3 Tape Controller

The Corvus interface for the Bank uses a WDlOlO, 40-pin, MOS/LSI chip as the main controller of the Bank. The WDlOlO is manufactured by Western Digital Corporation. It is designed to control Winchester disk drives, but has been implemented as the Bank controller. The WDI 01 0 is ideally suited as the Bank controller because it can be directed by the 6801 microprocessor in order to perform unique Bank commands.

The 6801 microprocessor directly issues commands to the WDlOlO. The commands are: Restore, Seek, Read, Write, Scan ID, Format. Before issuing these commands the WDlOlO must be informed of parameters for these commands.

This is accompli~hed via .task files. !ask files are simply registers within the WDlOlO that can be directly accessed by the 6801. Task files specIfy on whIch track, sector, etc., to perform the specified command. For instance, a task file can be set up for track 4; executed by a format command, only track 4 would be formatted.

00·07

WD WCLK MAGNITUDE

COMPARATOR

RE

-.

I

WE -1

3 _•

A2-AO ...

RCLK HOST

IRQ IFC

MR RD

CS PLA

CONTROLLER STEP

DIRC

BCR EARLY

BRDY BUFFER ^LATE

IFe DRDY

BDRQ WF

BCS TKOOO

INDEX

VCC~ SC

VSS~ RWC

WG RG DRUN

Figure 2-3. WDIOIO Architecture

(Western Digital Coporation, Storage Management Products Handbook, 1984, page 211.)

The WDlOlO uses an internal microcontroller called a programmable logic array (PLA). It controls the flow of data throughout the chip, formats the data, and recognizes and processes commands.

A magnitude comparator is also internal to the WDlOlO. This 10-bit comparator calculates drive step, direction, and present and target track position.

The Modified Frequency Modulated (MFM) data is encoded and decoded by the WDlOlO. The frequency of the encoder is equivalent to the write clock and the bit rate while the decoder frequency is generated by the read clock and the data separator.

The address mark detector (AM Detect) checks the incoming data stream for a unique missing clock pattern used in each ID and data field.

The Interface Circuit controls and monitors all lines to and from the tape with the exception of the read and write lines.

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2.4 Read/Write CPU Board

All read and write functions to and from the Bank are controlled by the Read/Write CPU board. The intelligence of this board is derived from an Intel i8749 microprocessor. The Read/Write CPU board receives input signals from the OMNINET Bank Controller board and the tape drive mechanism. It outputs signals to the Tape Mechanism as well as the servo board.

W

MOTOROIN DIRECTION SELECT STEP WRITE GATE DRIVE SELECT RESET

WRITE DATA RITE PROTECT

AUTO CLEAR

2.4.1 i8749 Microprocessor

--

^READ

- _...

WRITE

~

-

... ~

-

...

-

_...

-

_....

....

-

_CPU

-

18749

-

- -

-- -

- - _- -

Figure 2-4. R/W Board Block Diagram

"" READ DATA

-

READ/WRITE

- -

^HEAD

•

^{TAPE MARK}

-

TRACK ZERO

- - -

^{TAPE RUN}

~ UNDER TRACK ZERO

- --

CASSETTE BUCKET

...

UNLOADING MG

~

-

^{TAPE CURB}

... PINCH ROLLER MG

-

"" STEPPER MOTOR

-

^SERVO_BOARD

The Intel i8749 microprocessor performs the major control tasks on the Read/Write board. It has a 2K X 8 bits program memory, a 64K X 8 RAM data memory, 27 I/O lines, an 8-bit timer/counter and built-in oscillator and clock cir- cuits. The i8749 controls three major mechanical operations; they are the tape run control, tracking control and input signal detection.

13

. - - - -- - - - -... ----

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The tape run control function is responsible for:

• Motor ON-OFF Control-Controls the switching of the servo motor to the ON and OFF states.

• Pinch Roller Solenoid Control-Controlling the solenoid which holds the tape between the capstan and the pinch roller when the tape is running.

• Unload Solenoid Control-Activating the solenoid and releasing the load arm when the servo motor stop signal is generated. This reduces shock to the tape during the transition from high speed operation to a complete stop.

• Tape Hold Solenoid Control-Maintaining the solenoid acts to insure tape positioning.

• Tape Run and Servo Lock Detection-Signals the CPU via a photo transistor that the tape is running and provides the tape speed.

The tracking control function is responsible for:

• Stepper Motor Drive-Controlling the stepper motor which moves the read and write head from track to track.

• Track Zero Detection- Detecting when the head is over track O.

• Under Track Zero Detection- Detecting whether the head is lowered below track 0 and, therefore, in an unusable position.

The input signal detection function is responsible for:

• Motor On/Off-Sensing whether the motor is presently in the OFF or ON state.

• Step Signal Detection-Detecting the head step signal when it is stepping from track to track.

• Direction Select Signal Detection-Detecting which head direction is selected.

• Write Gate Signal Detection-Sensing if a write is being performed to inhibit track movement.

• Cartridge Detection-Detecting whether a tape cartridge is properly inserted in the cartridge holder.

2.4.2 Auto Clear Circuit

A key circuit on the Read/Write CPU board is the Auto Clear (or reset) circuit Its purpose is, upon power up of the Bank, to reset the i8749 and the stepper motor drive circuit as soon as voltages are stable.

~---~~---~---,-~~---o+5V

+ C10 os ^18V

RA9

D9

R10

13

RA7 RA7

I~8

RA7 ^C14 ^R12

Figure 2-5. Auto Clear Circuit

As the power is applied to the circuit, the differentiating circuit (CI0 & RIO) changes the base to 'high' and turns on transistor Q8. The current then flows from the collector to the emitter and the collector voltage changes to 'low' sending a 'low' signal to pin 4 of the CPU, causing the CPU to be reset.

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A short time after the power is switched on, the impedance of C10 rises and current will no longer flow to the differentiating circuit. When the voltage at 'A' exceeds 5.1 VDC, current will then flow to the zener diode D4 and the input condition of the comparator IC 11 will be

v- >

V+. The base voltage at Q8 changes to 'low' and Q8 turns off, releasing the reset condition of the CPU.

Since the voltage charge in C26 at the moment that the power is switched off is 4.3 VDC and the voltage charge at C4 is approximately 5.7 VDC, the condition of the comparator (IC11) is V-

>

V+. This causes the potential at pin 4 of the CPU to be maintained at a 'high' level.

When the discharge of C14 is complete, the input condition of the comparator changes to V+

>

V- because C26 is continuing to discharge, therefore the potential of pin 4 of the CPU changes to a 'low: allowing the reset state to continue. The RA7 and C14 combination form a circuit to delay the reset signal.

2.4.3 Stepper Motor Drive Circuit

The stepper motor drive circuit drives the head tracking motor. When the WD1010 sends a step pulse to the i8749, the i8749 will activate the stepper motor by providing a sequence of 8 pulses to the four coils in the stepper motor.

These series of pulses will cause the motor to tum and move the head one track. The order in which the coils are activated by the i8749 determines the direction of head movement.

+18V

+5V O--.... - - - - -.... ---+-4~

.... ---... ..,

RA3 RA13

COMMON

AUTO CLEAR

CIRCUIT o-... -~D~PH~A~S~E---

o---~~~~~~ ^DPHASE

CPHASE

<CPU

BPHASE

A PHASE

RA2 A PHASE

CN2

Figure 2-6. Stepper Motor Circuit

IC2 is a set of quad NOR gates which control transistors Q4, Q5, Q6, and Q7. Any 'Low' inputs from the CPU at pins 21 to 24 will produce a high output which turns on transistors Q4, Q5, Q6, Q7 to operate coils A, B, C, and D of the stepper motor.

An overdrive circuit is provided which is made up primarily of a NOR gate (lC4), an inverter (IC5), a transistor (Q3), and resistor R5. As the stepper motor operates, the CPU inputs a 'low' via pin 36 to the input of IC4 at pin 4 and the Auto Clear circuit provides a 'high' signal to IC4 at input pin 5. The output of IC4 then goes 'high' which then turns on transistor Q3, allowing +18 VDC to be delivered to each common pin of coils A, B, C, and D of the stepper motor.

When the motor is stopped, the signal on pin 36 of the CPU goes 'high' to tum transistor Q3 off. At this time a voltage of 18 VDC is supplied to the stepper motor through resistor R5. Consequently, a low voltage is supplied to the stepper motor to hold it :in the stop position without generating an excessive amount of heat.

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For the head to travel up (toward track 100) and down (toward track 0), the coils are sequentially activated in the following phases:

Condition Active Coils

Stopped A&B

Ascending A & B, B & C, C & D, and D & A (Toward Track 101)

Descending A & B, D & A, C & D, and C & D (Toward Track 0)

Table 2-1. Coil Activating Sequence 2.4.4 Index Detection Circuit

Because continuous loop tape is used in the Bank, a marker is required to indicate the beginning location of the tape.

This is accomplished with a combination of a phototransistor, LED, and a small piece of reflecting splicing tape on the backside of the tape. This index mark is detected by the phototransistor which is mounted next to the capstan pinch roller.

The index detection circuit causes the LED to light and then receives the reflection of the index mark from the phototransistor. A pulse is generated by this circuit and passed through pin B4 of connector CN4 to pin 29, TAPE MARK signal, of the WDI0I0.

R1!5

C1!5

Figure 2-7. Index Detection Circuit

R29 TAPE MARK

1- -I

^SENSOR

1 _ _ 1

When the splicing tape is not aligned with the tape mark sensor, the comparator output is in a 'high' state and the external output of IC19, pin 6 is at a 'high' state when the servo motor is operating at a constant speed. When the splicing tape is aligned with the tape sensor, the comparator output changes to a 'low' state, creating a 'low' state at the output of IC19 pin 6.

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2.4.5 Track Zero Detection Circuit

Track 0 detection circuit informs the i8749 if the head is located at track O.

PIN l' CPU

RAg

R31

RA8 RA8

Figure 2-8 Track Zero Detection Circuit

ZERO TRACK SENSOR

- - -

I

I _{- - -} I

The track 0 detection circuit is very simple. An LED and a phototransistor are placed in alignment above and below the two track 0 sense gears. Each gear has a single small hole near its outer edge. When the gear holes align allowing the LE.D to excite the phototransistor, it signals the comparator that the head is at track O. The comparator (lCll) then outputs a 'low' signal to the CPU at pin 1. When there is no light detected by the photo transistor, the comparator outputs a 'high' to the CPU.

2.4.6 Cartridge and Holder Detection Circuit

The cartridge detection circuit uses a leaf switch as a detector to notify the CPU that there is a cartridge properly positioned in the cartridge holder. In series with the cartridge detection switch is the cartridge holder detection switch.

A normally closed switch, it momentarily opens when an operator opens or closes the cartridge holder.

The two leaf switches are arranged in series and perform functionally as an AND gate. Both switches must be set, i.e. a cartridge must be inserted and the holder must be set in order for the proper signal to be sent to the CPU.

Also in series with these two switches is the Bank RESET switch. The RESET switch is located at the rear of the Bank cabinet between the power receptacle and the on/off switch. A momentary open switch, it performs the same function as the cartridge holder detection switch. If for some reason the tape servo motor will not stop spinning, pressing this switch will stop the motor.

2.4.7 Write Protect Detection Circuit

The Bank tape uses a write protect tab on the bottom of the cartridge to enable write protection. If the tab is broken off, the write protect circuit detects it by means of a leaf switch and disables the write operation by a sending signal to the CPU.

2.4.8 Under Track Zero Detection Circuit

This switch is located under the read/write head. In the event that the head should travel below track 0, the under track zero detection switch sends a signal to the i8749 processor. The result of this condition will appear to the WDI0I0 as a tracking error (see table 2-2).

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2.4.9 Error Circuit

The error circuit enables the CPU to send an error signal to the WDI0I0 when a tape run error or tracking error has occurred. The signals to the controller in the fonn of 'high' and 'low signals are output from the CPU at pin 33 and 34.

i8749 i8749

Status Pin 33 Pin 34

Normal High High

Tape Run Error High Low

Tracking Error Low Low

IC9 Reset Low Low

--

Table 2-2. CPU Error Signal Status 2.5 Servo Assembly

The Bank servo board is responsible for controlling the tape servo motor. The only electrical adjustment which can be made to the Bank is the servo motor speed adjustment on this board. It is located behind the tape drive mechanism and in front of the power supply. The block diagram below illustrates the general operation of the servo board.

... m

~

8

"

CPU 18748

IC2 SERVO CONTROLLER

I:

~

o z

1 - - - 1

1 1

1 1 1

, ,

,

, ,

, - _ _ _ _ _ _ 1

FGAMPAND

~---tWAVEFORMSHAPING t - - - ' CIRCUIT

Figure 2-9. Servo Board Block Diagram The servo board can be divided into five major sections:

• Servo Controller Chip

• Constant Voltage Circuit

• Differential Amplifier Circuit

• Motor Driver Circuit

• FG-AMP and Waveform Shaping Circuit

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2.5.1 Servo Controller Chip

Most of the servo control function is provided by IC2 (TC9142P) on the servo board.

GND-1 16-VCC

XT-2 15-CPOUT

XT-3 14-CPIN

NI~4 SERVO 13-STROBE¢

CONTROL

N2-5 IC

12-LD TL9142P

FG IN-6 11-P/S

APC^u7 10-33/45

AFC-& 9-RV

Figure 2-10. Servo Control IC

The servo controller is an 8-bit digital to analog converter which is used for speed control (AFC) and phase control (APC).

2.5.2 Constant Voltage Circuit

This circuit provides a constant 7.5 VDC to the Servo Controller IC2.

+7.5\1 Q& +12V

C10

+

C11

.-.----e

^R13

Figure 2-11. Constant Voltage Circuit

When 12 VDC is applied to the circuit, current flows through R13 to ZD1. The anode of ZD1 and the base of Q8 are maintained at 8.2 VDC. Then, current flows from the base to the emitter and Q8 provides the necessary current to the load circuit. The emitter potential of Q8 drops below the base potential by approximately 0.7 VDC to 7.5 VDC.

Thus Q8 supplies a constant voltage to the load circuit at the same time it supplies the necessary current.

19

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2.5.3 Differential Voltage Amplifier Circuit

The differential voltage amplifier circuit amplifies the weak signals of APC and AFC from IC2 and feeds them to the motor drive circuit. It does so by using an operational amplifier, ICI, to maintain the servo motor speed at 3600 RPM

R38

C14 +12V

R21 VR1 R22

R23

AFC t---~IV\,..._+_--__I R25

APC t---'V-~--I

IC2

Figure 2-12. Differential Voltage Amplifier Circuit

MOTOR DRIVER CIRCUIT

The voltage output of APC and the AFC indicate the voltage deviation from the motor reference speed. The operational amplifier amplifies this voltage to maintain the motor at the reference speed. VRI is a control to maintain the servo- motor at 3600 RPM.

2.5.4 Motor Driver Circuit

The motor driver circuit provides the voltage necessary to turn the servo motor at a constant speed. This voltage is provided by a combination of the output of the differential amplifier and the MOTOR ON signal from the CPU.

+18V

+ C2 A28

R3 A4

Q4

Figure 2-13. Motor Driver Circuit

POWER TRANSISTOR

1---1 1

1 1 1 _ _ _ 1

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When the motor ON signal from the CPU is at a 'high' level, a 'high' signal is applied at the base of Q3 to tum on the transistor. When this happens the signal from the voltage amplifier circuit is not delivered to. the base of transistor Q4 and the servo motor does not operate.

When the motor ON is 'low', transistor Q3 is turned off and the current from the error voltage amplifier is amplified by transistors Q4 and Ql. The amplified current flows into the base of the power transistor, allowing the control voltage to be applied to the servo motor to activate it.

Transistor Q5 is used to prevent overcurrent to the servo motor. If an overcurrent flows through the motor, a voltage of 0.7 VDC is generated at resistor R26 to tum on Q5 and Q3, allowing no current to flow to the servo motor. R3, R4 and C2 form a circuit which prevents a momentary overcurrent from flowing through the base of Q5.

2.5.5 FG-Amp and Waveform Shaping Circuit

The FG-Amp and waveform shaping circuit amplifies and shapes the FG-IN signal from the PG coil and inputs it into IC2.

+7.5V

09

FGIN~---.----~

R18 IC2

+5

»-~~~~--u

FGIN AFCu- . - - . __ •

OUT

C12

Figure 2-14. FG-Amp and Waveform Shaping Circuit

When the signal from the PG coil is input to the base of transistor Q7, Q7 turns on only when the base input voltage exceeds approximately 0.7 VDC which is the voltage drop between the base and the emitter. At the same time Q9 and Q10 turn on allowing the FG-IN signal of 7.5 VDC to be input to IC2.

2.6 Power Supply and Fuse

The Bank power supply provides +5 VDC, +12 VDC, and +18 VDC. All voltages have a ±0.1 volt tolerance. Both the 100-120 VAC and 220-240 VAC models use a 250 Volt, 2 Amp fuse.

- - - -21 --- -_ . . . _--

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CHAPTER 3 DISASSEMBLY/ASSEMBLY

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CHAPTER 3 DISASSEMBLY/ ASSEMBLY

This chapter describes the disassembly and assembly procedures for the Bank Instructions for replacement of modules is included.

3.1 Introduction

Disassembly of the Bank is simple due to its modular design. The basic subassemblies are:

• OMNINET Bank Controller Board

• Read/Write CPU Board

• Servo Board

• Power Supply

• Power Connector and Switch

• Tape Cartridge Holder

• Tape Drive Mechanism

The following are needed for disassembling the Bank:

• Phillips screwdriver (a #2 screwdriver can be used for most disassembly procedures. A #1 may be necessary for some screws.)

• Small flat blade screw driver 3.2 I>isassenBbly

WARNING:

Before beginning, turn off the AC power and remove the cord. Disconnct the tap cable from the network.

3.2.1 Cartridge Holder

The cartridge holder must be removed before cleaning the head or removing the top encasement cover.

1. Remove the tape from the holder if a tape is in place. With the AC power off and the power cord discon- nected, remove the OMNINET tap cable from the rear of the cabinet.

Figure 3-1. Tape Cartridge Holder

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2. Remove the cartridge holder by gently spreading the rear-most support arms until the pins are free. Lifting the rear of the holder, slide the entire holder toward the back of the cabinet. Remove the holder from the front support arms when the front pins reach the wide end of the slots.

CAUTION:

Do not attempt to remove the foam top from the cartridge holder.

3.2.2 Top Encasement

Before removing the top encasement, the cartridge holder must be removed; refer to section 3.2.1 for instructions.

1. Locate the two phillips screws beneath the ridge of the front bezel and remove them. Locate the two phillips screws at the rear bezel and remove them.

2. Carefully lift the top encasement until the cable from the front indicator LED PCA is accessible at the Read/Write board. Disconnect at the Read/Write CPU board and lift the top assembly out and away.

3.2.3 LED Board

Remove the top encasement (section 3.2.2) before removing the LED PCA. The LED board should be removed only to service the board or when an exchange of a damaged top encasement is made.

1. Locate the LED board in the top half of the encasement and unlock the cable retainer securing the wiring to the encasement.

2. Using a flat-bladed screw driver, gently pry the LED board away from the front bezel, taking care not to stress the LED leads.

3.2.4 OMNINET Bank Controller Assembly Remove the top encasement (section 3.2.1).

1. Locate the Omninet Controller board as shown in illustration 1-2. Remove the 34-pin flat ribbon cable J3, from the connector on the Omninet Controller board.

2. Remove the power connector J2 at the base of the controller board and lift the board up and out of the slot.

26

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3.2.5 Read/Write CPU Assembly

The OMNINET Bank Controller board should be removed (3.2.4) prior to removing the Read/Write CPU board.

1. Locate the Read/Write CPU board shown in Figure 3-3. Remove the cable going to the Read/Write head;

note the correct connector orientation.

Figure 3-2. Read/Write CPU Board

2. Remove the power cable from the power supply. You may have to lift the Read/Write CPU board partially out of the slot to access the connector.

3. Remove the cable leading to the Bank servo board.

4. U£t the Read/Write CPU board completely out of the slot, disconnecting the wiring harness leading to the underside of the tape drive mechanism.

5. Remove the 34 pin flat ribbon cable from the Read/Write CPU board.

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3.2.6 Servo Board

Removing the tape drive mechanism before removing the servo board, although not necessary, will allow easier access. Refer to section 3.2.10 of this chapter to remove tape mechanism.

1. Disconnect the five wire connector (CN1) which leads from the servo board to the underside of the tape mechanism.

2. Disconnect the eight wire connector (CN3) leading to the Read/Write CPU card.

NOTE:

If the servo board is being removed without removing the tape drive mechanism, it will be easier to disconnect this after the mounting screws have been removed as in step 3.

3. Remove the two mounting screws which hold the servo mounting bracket to the chassis and lift out the servo assembly.

To remove the servo board from its mounting bracket:

1. Unscrew the transistor mounted cable from the mounting bracket.

2. Squeeze the retaining flanges of the plastic stand-offs together and pull the board off the bracket.

3.2.7 Bottom Encasement

Before the Bank chassis can be removed from the bottom encasement the top encasement (section 3.2.2) must be removed.

1. Supporting the front end with one hand, slide the Bank forward until the front edge extends about 2 inches over the edge of the work table. Remove the two mounting screws from below with a Phillips screw driver.

2. Slide the Bank back, securely onto the work table. Turn the Bank 180 degrees, the back now facing the edge of the work table, and repeat step 1 to remove the two rear screws.

3. Replace the Bank securely onto the work table. The entire chassis may now be removed from the bottom encasement by lifting straight up.

3.2.8 Power Supply

The Bank chassis must be removed from the bottom encasement to access the power supply mounting screws. See section 3.2.7 for instructions.

The procedure for removing the power supply assembly from the chassis is similar to that for removing the chassis from the bottom encasement. The Bank chassis rests flat on the work table. The unit is slid forward until the power supply mounting screws can be accessed from below.

1. Unscrew the grounding wire from the chassis.

2. Remove the tie wrap which holds the cable to the OMNINET Bank Controller board to the chassis.

3. Disconnect the AC power line from the AC switch assembly.

4. Place the Bank chassis so the power supply is near the edge of the work table. Supporting the chassis with one hand, side the chassis forward over the edge about 2 inches. From below, remove the screws mounting the power supply bracket to the chassis.

5. Slide the chassis completely onto the work table. Lift out the power supply assembly.

3.2.9 AC Power Assembly

The AC power assembly can be removed after the top encasement has been disassembled; no other modules need to be disassembled.

1. Disconnect the AC power line leading to the power supply. (If the power supply has been removed, this disconnection will have already been made.)

28

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ACPOWER

TO POWER SUPPLY

Figure 3-3. AC Power Assembly Connectors 2. Unscrew the earth ground wire from the chassis.

3. If this was not done to remove the mechanism previously, disconnect the wires from the RESET switch to the tape drive mechanism; note the correct orientation for reassembly.

4. Remove the two mounting screws securing the AC power assembly to the chassis. Lift the assembly out.

3.2.10 Tape Drive Mechanism

It is not necessary to remove the cartridge support assembly to remove the tape drive mechanism.

1. Disconnect the wires from the mechanism to the RESET switch.

NOTE:

When viewed from the rear, the wires exit the connector towards the left and that the connector attaches to the UPPER two pins on the switch assembly.

2. Remove the Bank mechanism from the stand-offs by removing the four screws at the comers of the Bank tape mechanism.

3. lift the mechanism slightly away from the servo and Read/Write CPU boards to allow clearance for removing the eight-wire connector from the Servo board, and the wire harness from the Read/Write CPU board.

3.3 Ileassembly

To reassemble the Bank, reverse the procedures described in section 3.2.

3.3.1 Head to Ilead/Write Board Connector

To reconnect the head connector to the Read/Write CPU board, be sure that the ground wire of the five pin connector is at the top of the connector (pin #5).

3.3.2 IlESET 'Connector

The connector from the tape drive mechanism to the RESET switch plugs onto the top two posts of the RESET switch.

The wires exit the connector to the left when viewed from the rear.

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CHAPTER 4 DIAGNOSTICS

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CHAPTER 4 DIAGNOSTICS

This chapter provides a general description of the use of the Bank diagnostic program, BDIAG; instructions for running the program are NOT included. For instructions and additional information on the Bank diagnostics see the Bank Diagnostic Guide.

4.1 Introduction

BDIAG is used to find and correct media defects which cause errors and degrade the performance of the BANK The diagnostic also provides a means of checking:

• Firmware Version

• Bank Parameters

• Spare Blocks Table 4.2 Diagnostic Functions

This describes the diagnostic functions available in the BDIAG program. The Corvus diskette labelled "Bank Diag- nostic Utilities" contains the BDIAG program.

When BDIAG is run the following menu appears:

V - VERSION check

P - Display BANK PARAMETERS C - Perform Verify-scan for bad tracks D - DISPLAY or alter spare block tables R - RECOVER format results

F - Perform tape FORMAT S - SET diag data block file name

L - Read version LEVEL of Diag Data Block I - Modify INTERLEAVE

U - UPDATE firmware on BANK N - Write tape NAME

W - WRITE Corvus volume E - Exit

4.2.1 Version Check

The V option gives information about the Bank. This option is not destructive to data on the tape. Version Check gives the following information:

• Tape capacity in 512-byte blocks

• Sectors per Track

• Tracks per Bank

• Firmware Revision level

• Tape time (in hours)

• Start/Stop count

Tape time is the total number of hours the tape has been used. Corvus recommends a maximum tape life of 500 hours.

Start/Stop count is the number of times the tape has been stopped and restarted. The start/stop count on a reliable tape should not exceed 500.

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4.2.2 Display Parameters

The P option is the display PARAMETERS option. This option gives the parameters which include:

• Cartridge Name

• Cartridge Length (in meters)

• Interleave Specification 4.2.3 The C Option

This gives a choice between Verify and Certify; You are prompted to type V or C to continue.

4.2.3.1 "er~

Verify can be performed on the entire tape, or specific tracks of the tape. VERIFY takes approximately 35 minutes on a 100-MB tape, and 70 minutes on a 200-MB tape. To VERIFY a single track takes approximately 1 minute on a 100-MB tape, and 2 minutes on a 200-MB tape.

4.2.3.2 Certify

CAUTION:

CERTIFY is destructiive to data. Backup the tape before certifying whenever possible.

The CERTIFY function, like VERIFY, checks the CRC checksum of each Sector, but unlike VERIFY, it checks the media four times, and automatically spares bad blocks.

Since CERTIFY performs media checks four times, it ensures a more reliable check than VERIFY; however, this is at a considerable cost in time.

A 100-MB tape takes approximately five hours, and a 200-MB tape about 10 hours to CERTIFY.

To CERTIFY a track takes approximately 31/2 minutes on a 100-MB tape, and 61/2 minutes on a 200-MB tape.

It is recommended that VERIFY be run first to identify bad sectors, then each track containing those sectors may be certified individually.

4.2.4 Display or Alter Spare Blocks Tables The D option allows you to do the following:

• DISPLA Y the contents of the spare block table.

• CONVERT a logical block number to a physical one.

• Show the RANGE of blocks a track contains.

• ADD a block to the spare block table.

• DELETE a block from the spare block table.

4.2.5 Recover Format Results

The R option displays the contents of a file containing the results of a FORMAT of the tape. When FORMAT is run, bad blocks are spared automatically by the FORMAT program.

The results are listed in the BNKRSLTS.TEXT file (or an alternate file, if specified).

4.2.6 Format

The F option allows the user to format new tapes or to reformat a tape suspected of having errors in the sector address or header portion(s) of a sector.

CAUTION:

FORMAT is destructive to data.

34

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4.2.7 Set Diag Data Block Filename

The S option allows the user to set the name of the data file for the Bank diagnostic program. The BDIAG program defaults to BK.DIAG.DATA for this file name.

4.2.8 Read Version Level of Diag Data Block

The L option gives the version number of the data file the Bank Diagnostic program uses; you may be asked for this number by a Corvus service representative before performing the S option (see 4.2.7 above).

4.2.9 Modify Interleave

The I option allows the user to modify the interleave factor for the tape. BDIAG defaults to 11 as an optimum interleave factor. Before changing the interleave factor, back up the Bank tape.

Refer to chapter 3 of the Bank Guide, and the "Resetting the Interleave Factor" section of the Bank Diagnostic Guide for instructions and additional information on using this option.

4.2.10 Update Firmware

The U option allows the user to UPDATE the Bank firmware to a new revision level, or rewrite the existing firmware on the tape in case the firmware was damaged.

The firmware is the Bank operating system software; it resides on track 1 of the tape. If the firmware becomes damagecL it win cause the Bank controller to give error messages to the host Computer, or fail to function at all.

When this happens, the user must attempt to write a new copy of the firmware to the tape, using the U option.

4.2.11 Write Tape Name

The N option allows the user to assign a unique NAME to each tape, so that the contents may be easily identified.

4.2.12 Write Corvus Volume

The W option allows the user to write the Corvus volume on the tape; the Corvus volume contains information that the Constellation II software requires.

This option is not normally used; however a Corvus Service Representative may ask you to WRITE the Corvus volume if it is suspected of being damaged.

This option is included as an option when FORMAT is run; when selected with FORMAT, the Corvus volume is written automatically when formatting is complete.

4.3 Inactivating Bad Tracks

Up to four sectors can be spared on each track. If more than four sectors contain bad blocks (each sector contains two blocks), the entire track must be inactivated.

Inactivating a track creates a new, empty volume to place over the bad track; the volume is not granted write access and prevents the track from being used to store Data.

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CORVUS SYSTEMS THE BANK SERVICE MANUAL

FCC WARNING

CORVUS SYSTEMS THE BANK SERVICE MANUAL

TABLE OF CONTENTS

TABLE OF CONTENTS

LIST OF FIGURES AND TABLES

LIST OF FIGURES AND TABLES

SPECIFICATIONS

SPECIFICATIONS

o

liz

CHAPTER 1

GENERAL DESCRIPTION

CHAPTER 1

GENERAL DESCRIPTION

+-ta*======================>

~::~:::::§~a==~~Li1I:'---

--

CHAPTER 2

FUNCTIONAL DESCRIPTION

CHAPTER 2

FUNCTIONAL DESCRIPTION

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CHAPTER 3

DISASSEMBLY/ASSEMBLY

CHAPTER 3

DISASSEMBLY/ ASSEMBLY

CHAPTER 4

DIAGNOSTICS

CHAPTER 4 DIAGNOSTICS

CHAPTERS

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